POD John C Calhoun decides to support the acquisition of all of Mexico, where in OTL he was opposed to it. In TTL he considered Mexico a place to expand slavery to. Thus, with Calhoun rallying the support of the South, the United States force Mexico to disband their government, and it becomes a territory of the United States in 1848. There was relatively little resistance by the population because of the unpopularity of the Santa Anna Government.